It was also found that the concentrations of mycoplasmal DNA in TBLF were low, but not absolutely negative in all pigs before challenge and in control pigs at day 17–18.
Since the pigs were derived from a commercial herd considered free of mycoplasmal pneumonia, it is possible that either TBLF contained low amounts of DNA from
avirulent M. hyopneumoniae strains or from organisms other than M. hyopneumoniae that cross-react in the qPCR